Technical Field
The present invention relates to an electric vehicle, and more particularly to a structure of an electric vehicle driven by a synchronous motor and an induction motor, and a control method of the electric vehicle.
Related Art
Recently, electric vehicles driven by an electric motor are in widespread use. There are many types of electric motors such as permanent-magnet type synchronous motors, induction motors, and reluctance type motors, with various characteristics. Therefore, it is proposed to configure a drive system of an electric vehicle with desired functions by combining characteristics of two or more types of electric motors to achieve mutually complementary characteristics (refer to, for example, JP H07-15804).
JP H07-15804 proposes a drive system which drives front wheels by a permanent-magnet type synchronous motor with high efficiency and a small capacity, and drives rear wheels by an induction motor with a large capacity and a high base speed. In this drive system, a method is proposed to distribute a drive torque requirement issued through a gas pedal to a torque command for the permanent-magnet type synchronous motor and a torque command for the induction motor based on various conditions such as a rotation speed of the front wheels and the rear wheels, acceleration speed, tilt angle of a vehicle body, battery voltage, electric current, temperature of an electric motor, uphill or downhill, in acceleration or deceleration, and a state of a road surface.